Many types of communications can be performed over data networks (wireless and/or wireline networks), including electronic mail, web browsing, file downloads, electronic commerce transactions, voice or other forms of real time, interactive communications, and others. To enable the establishment of communications sessions in a network, various control functions are deployed in the network. Some standards bodies have defined subsystems within communications networks that include such control functions. One such standards body is the Third Generation Partnership Project (3GPP), which has defined an Internet Protocol (IP) multimedia subsystem (IMS) protocol that includes various control functions for provision of IP multimedia services, including audio, video, text, chat, or any combination of the foregoing.
An IP multimedia subsystem can be used in conjunction with a wireless access network, such as a wireless access network according to the GSM (Global System for Mobile) or UMTS (Universal Mobile Telecommunications System) standard, as defined by 3GPP, a wireless access network according to the CDMA 2000 (Code Division Multiple Access 2000) standard, as defined by 3GPP2; or other type of wireless access networks. An IP multimedia subsystem can also be used with wireline networks.
An issue associated with deploying IMS services is the cost associated with deploying the infrastructure to implement the IMS services. The infrastructure for deploying IMS services can be complex. The relatively high costs associated with deploying IMS services can cause service providers to delay such deployment.